Unix dump

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* [https://github.com/bitsgalore/unix-dump-magic Unix dump format] - includes some minimal sample files, created for testing magic patterns  
 
* [https://github.com/bitsgalore/unix-dump-magic Unix dump format] - includes some minimal sample files, created for testing magic patterns  
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 +
== Restoring the contents of a dump file  ==
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 +
To restore the contents of a dump file on a Unix system, first the install the "restore" tool. On Debian-based systems:
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<code>sudo apt install dump</code>
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Then go through the following steps:
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<ol>
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<li><p>Create an empty directory, and go to that directory in the command terminal:</p>
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<code><p>mkdir extracted</p></code>
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<code><p>cd extracted</p></code>
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<li><p>Run <code>restore</code> in interactive mode on the dump file you want to extract<ref><p>If you don't run <code>restore</code> as sudo, extraction results in a flood of <code>chown: Operation not permitted</code> messages (the files ''are'' extracted though).</p></ref>:</p>
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<code>sudo restore -if ../../tapes-DDS/1/file000002.dd</code></li>
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<li><p>Inspect the contents of the dump file:</p>
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<code>restore &gt; ls</code>
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<p>Result:</p>
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<pre> 5bin/        diag/        kvm/        mdec        share/      ucbinclude
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5include/    dict/        lddrv/      net          spool        ucblib
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5lib/        etc/        lib/        nserve      src          xpg2bin/
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adm          export/      local        old/        stand        xpg2include/
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bin/        games/      local-/      openwin/    sys          xpg2lib/
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boot        hosts/      lost+found/  pub          tmp
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demo/        include/    man          sccs/        ucb/</pre></li>
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<li><p>Use the <code>add</code>command to add directories that are to be extracted to the directory list. To extract everything:</p>
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<code>restore &gt; add .</code></li>
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<li><p>Run the <code>extract</code> command:</p>
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<code>restore &gt; extract</code>
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<p>This results in the following prompt:</p>
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<pre> You have not read any volumes yet.
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Unless you know which volume your file(s) are on you should start
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with the last volume and work towards the first.
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Specify next volume # (none if no more volumes):</pre></li>
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<li><p>Now enter <code>1</code>. Response:</p>
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<pre>set owner/mode for '.'? [yn]</pre></li>
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<li><p>Enter <code>n</code> <ref><p>This needs further investigation, as the implications of this setting are not 100% clear to me.</p></ref></p></li>
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<li><p>When the extraction is finished, exit the interactive restore session:</p>
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<code>restore &gt; q</code></li></ol>
  
 
== References ==
 
== References ==

Revision as of 17:17, 29 January 2019

File Format
Name Unix dump
Ontology
Extension(s) {}
MIME Type(s) {}
PRONOM {}

dump is an archive format that is written by Unix dump, which is a backup program that was popular in the '90s (reference?). Dump files were often written to tape. Dump files can be read using the restore tool. It appears that no specifications exist.

Contents

Variants

There are a number of variants to the Unix dump format.

The file(1) magic definition of the format makes a distiction between 'old' and 'new' filesystem variants. Each of these can be big-endian or little endian. In addition a 16-bit subtype of the 'old' variant exists. Finally there is also a ufs2 variant (which again can be big-endian or little endian). In total this results in 7 variants of the format. According to the restore documentation, the dump file format changed in version 4.4 (of the dump tool?).

Software

Documentation

Sample files

  • Unix dump format - includes some minimal sample files, created for testing magic patterns

Restoring the contents of a dump file

To restore the contents of a dump file on a Unix system, first the install the "restore" tool. On Debian-based systems:

sudo apt install dump

Then go through the following steps:

  1. Create an empty directory, and go to that directory in the command terminal:

    mkdir extracted

    cd extracted

  2. Run restore in interactive mode on the dump file you want to extract[1]:

    sudo restore -if ../../tapes-DDS/1/file000002.dd

  3. Inspect the contents of the dump file:

    restore > ls

    Result:

     5bin/        diag/        kvm/         mdec         share/       ucbinclude 
 5include/    dict/        lddrv/       net          spool        ucblib 
 5lib/        etc/         lib/         nserve       src          xpg2bin/
 adm          export/      local        old/         stand        xpg2include/
 bin/         games/       local-/      openwin/     sys          xpg2lib/
 boot         hosts/       lost+found/  pub          tmp 
 demo/        include/     man          sccs/        ucb/

  4. Use the addcommand to add directories that are to be extracted to the directory list. To extract everything:

    restore > add .

  5. Run the extract command:

    restore > extract

    This results in the following prompt:

     You have not read any volumes yet.
 Unless you know which volume your file(s) are on you should start
 with the last volume and work towards the first.
 Specify next volume # (none if no more volumes):

  6. Now enter 1. Response:

    set owner/mode for '.'? [yn]

  7. Enter n [2]

  8. When the extraction is finished, exit the interactive restore session:

    restore > q

References


Cite error: <ref> tags exist, but no <references/> tag was found
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